It is widely known that environmental conditions (e.g., temperature, relative humidity, barometric pressure, etc.) may impact various aspects of the printing process. Generally, the printing process involves the application of a colorant (e.g., ink, toner, etc.) onto a print medium. For example, in inkjet printers, dry air (i.e., low relative humidity) may exacerbate pen decap. In another example, in electrophotographic (“EP”) printers (e.g., laser printers, etc.), cold and/or dry air may affect toner transfer and thus, image quality and toner usage. Additionally, environmental conditions (“ECs”) may affect estimation of toner usage in EP printers.
To address the impact of ECs on the printing process, various conventional printing devices have sought to optimize the printing process for so-called “typical” ECs. However, as printing technology has improved, pixel size has generally been reduced. Along with this reduction in pixel size, a corresponding increase in the impact of ECs has occurred. For example, to decrease pixel size, toner particle size has decreased. In general, smaller particles may be more susceptible to fluctuations in electrostatic charge due to ECs which may lead to unacceptable print quality. Thus, the image quality of these conventional printing devices may only be acceptable for a relatively narrow range of ECs.
Additionally, some conventional printing devices modify certain printing processes by utilizing sensors to measure ECs in the vicinity of the printer. For example, U.S. Pat. No. 5,655,174, currently assigned to HEWLETT-PACKARD COMPANY, discloses a printing system including an ambient condition sensor for estimating the consumption of toner, the disclosure of which is hereby incorporated by reference in its entirety.
While a variety of methods exist to measure ECs, generally, each environmental condition (“EC”) or environmental factor (“EF”) requires a separate sensor. For example, relative humidity (“RH”) may be measured by Dunmore cells, Pope cells, and thin-rim capacitance meters. However, RH sensors are generally incapable of measuring temperature or barometric pressure. To measure temperature, typically a thermocouple or thermistor is utilized. To measure barometric pressure, typically a pressure transducer is utilized. Thus, to measure RH, temperature and barometric pressure, three sensors and their associated electrical components may be required. Each sensor added to a printer, or any other device, increases the cost and complexity of the printer or device.